1. Technical Field
The invention relates to a technical field of a blade supporting apparatus in a wiper apparatus which is equipped in a vehicle such as a private car, a truck, a bus or the like.
2. Description of Related Art
In general, in this kind of wiper apparatus, there is a structure such that a wiper blade provided in a leading end portion of a wiper arm, reciprocates forward and reverse so as to wipe a window surface on the basis of the normal and reverse rotation of a wiper shaft integrally mounted to a base end portion of the wiper arm. In this wiper apparatus, the structure is generally made such that a middle portion of the wiper blade is pivoted to the leading end portion of the wiper arm via a pivot substantially orthogonal to an arm length direction so as to freely oscillate, and the wiper blade wipes the window surface following the reciprocal and reverse oscillation of the wiper arm in correspondence to the normal and reverse rotation of the wiper shaft. In this wiper apparatus, for example, in the case that a long wiper blade wipes the window surface for a large-size wiper apparatus, or in the case that a range of the reciprocal and reverse oscillation is made wide, or the like, there is a case that a terminal end side, corresponding to a portion in the side of the wiper shaft of the wiper blade, tends to be late in a wiping speed in comparison with the leading end side, whereby a following property of the wiper arm is deteriorated.
Then, it is proposed to support the terminal end side of the wiper blade by a supporting member, provided in the wiper arm, so as to increase the following property of the wiper arm, for example, there is a structure described in Japanese National Stage Patent Publication 2001-501893 of WO99/05009. The supporting member in this structure is fixed to the wiper arm, and is structured so as to support the wiper blade at one side in the oscillating direction of the wiper arm. In this case, in recent years, the window surface tends to be formed in a curved shape, and the wiper blade oscillates in a direction of the window surface (a direction of moving close to or apart from the window surface) around the pivot corresponding to a supporting point with respect to the wiper arm. Accordingly, in this wiper apparatus, the structure is made such that a supporting concave portion, constituting the supporting member and formed in a concave groove shape, is provided in one side of the wiper arm, a support receiving body is integrally provided in the side of the wiper blade, and the support receiving body is slidably inward fitted into the supporting concave portion, thereby allowing the wiper blade to oscillate in the window surface direction.
In this case, the conventional supporting member mentioned above is structured such that the support receiving body oscillates in the window surface direction within the supporting concave portion, however, the supporting concave portion and the support receiving body are in a surface-to-surface contact state with each other.